The human eye is a complex organ composed of various different parts that each have specific functions.
Knowing what each part of the eye is named and its function allows you to better communicate your concerns with your eye doctor or to discuss eye health with others.
The Parts of Your Eyes
The front of the eye is called the cornea, sclera, and conjunctiva. The iris is the colored portion of the eye which surrounds the pupil.
The vitreous is the gelatin like substance that fills most of the eye behind the lens. The retina is the back of the eye responsible for vision.
Cornea
The cornea is the clear central portion of the front of the eye. The role of the cornea is to focus light into the eye.
The cornea is highly sensitive and is the region responsible for having dryness, burning, or feeling like there is something in the eye.
Since the cornea is very sensitive, any damage to the cornea can cause extreme pain and discomfort.
The cornea is the primary focusing element in the eye. This determines the need for glasses or contact lenses.
In some refractive surgeries, such as LASIK, the cornea is altered to change the focusing power.
Sclera
The sclera is the white portion of the eye. It is a tough structure that gives the eyeball its rigid form.
The sclera is primarily responsible for protecting and supporting the eye. It has several muscles attached to it which allow for eye movements.
Inflammation from diseases or allergies can cause redness in the sclera and the episcleral above it.
Conjunctiva
The conjunctiva is a thin, clear covering over the sclera and the inside of the eyelids. It is responsible for protecting the eye and keeping the eye from getting dry.
The conjunctiva has glands which help create the tear film and keep the surface of the eye from drying out.
There are blood vessels inside the conjunctiva which can rupture and cause a large red, bloody appearance to the eye. This is known as a sub conjunctival hemorrhage and is usually not a major concern.
Iris
The iris is the colored portion of the eye which surrounds the pupil, which is a central hole through the iris.
The function of the iris is to change the size of the pupil in response to light. In bright lights, the iris causes the pupil to constrict, or get smaller, to limit the amount of light that reaches the back of the eyes.
The iris color is determined by the amount of melanin in the iris and can change in cases where melanin is lost, such as Fuch’s Heterochromic Dystrophy.
Lens
The lens is a solid, clear portion of the eye which helps focus light in the eye and allows focus on near targets.
The lens is able to accommodate, or change the focus, to look at things near the eyes, such as a book.
This ability is diminished with age and is why reading glasses or bifocals become necessary.
Vitreous
The vitreous is a clear gelatin like substance which takes up most of the space inside the eyeball and has limited functions.
If the vitreous becomes cloudy or has damage it can affect vision or result in floaters.
Retina
The retina is the part of the eye at the back which collects light and results in vision. Having an intact and healthy retina is important for having clear vision.
Many diseases, such as diabetes, can affect the retina and cause damage which results in loss of vision, blurred or distorted vision, and distorted color perception.
Eye Health
Each portion of the eye has a role in maintaining good vision and it is important that if there is ever an issue with any part of the eye that you seek care from an eye doctor.
Knowing different parts of the eyes can enable you to give a better description of any issue you may be having and to help determine if something is not normal and needs medical attention.
Always consult with your eye doctor about anything that bothers you with your eyes or your vision!
